Volvo outdrive, can't keep it up overnight!

[msimms]

Volvo outdrive, can\'t keep it up overnight!

Yesterday afternoon the outdrives were put in the beach position to aid the application of antifoul. This morning the starboard drive was in the same posistion but the port had dropped down a couple of inches. During the course of the day it seemed to move down a further couple of inches.

The rams externally are dry, no leaks at all. There was a small leak internally, not sure where exactly, but that has now been fixed. Could it be that there is still some air in the system from the previous leak and it need to be bled out or is it likely to be something else? Any ideas? Engines are KAD43s.

Cheers

Mark

 

[mont]

Re: Volvo outdrive, can\'t keep it up overnight!

Hi,
This certainly sounds like basic hydraulic sag - bit like dont crawl under a car only supported on a hydraulic jack etc. Our forklift truck used to lower its cradle overnight if left in up position but no leaks.
Overnight would not be suprised if one starts to slowly drop.
There will be a leak - possibly just air escaping somewhere.
Would really consider that if it has only dropped a little overnight it will not affect normal use.
If there are no visible leaks of fluid apparent then its needle in a haystack to resolve or your oil level reservoir is too low.
Think a schoolboy physics answer might also relate to air temperature changing the volume of a liquid / gas ? Might also relate to lifting legs out of water and air entering system as air is thinner than water and can be sucked into system bypassing seals ?
Think i'd chock my legs and not trust the hydraulics before i stick my hand in the workings though - health and safety etc.
If it were mine and there was no leaks of fluid apparent anywhere then i'd live with it or you need some VP viagra if you cant sleep and you want to keep it up .....

 

[Dave_Snelson]

Re: Volvo outdrive, can\'t keep it up overnight!

Hi Mark - the question is - does the trim remain static when cruising along? If the trim on the leg alters (goes lower) then you have a problem that needs fixing. The oil leaks back into the reservoir passed the pump seals. Pumps are expensive to refurbish or replace!

If its all otherwise works OK, then there is no drastic need to fix it right now. My DP legs also lower slowly over a period of days and given that CI comes close to ground on low springs, I slip a noose over the prop cone and tie the legs up to the stern cleat - then it just can't lower! (remember to undo it though!).

Maybe bleeding the unit one more time may help, but I doubt it.

 

[msimms]

Re: Volvo outdrive, can\'t keep it up overnight!

>>> does the trim remain static when cruising along? <<<

That, at the moment is unknown. She's on the hard with the sea trial due shortly, sometime next week hopefully.

Do you think that as there is no external leak any fixing, if required, would be limited to inside the boat?

Cheers

Mark

 

[spannerman]

Re: Volvo outdrive, can\'t keep it up overnight!

If there is no visible oil leak externally or internally, and you haven't had to top up the oil reservoir then the problem is with the valves in the pump body, I'd get it looked at by someone who is familiar with hydraulics.
You may be lucky and its just a jammed valve thats not closing properly, or at worst its a new pump.

 

[Dave_Snelson]

Re: Volvo outdrive, can\'t keep it up overnight!

Yes - see spannermans reply. He's a man of greater knowledge than I.

 

[SeadogUSA]

Re: Volvo outdrive, can\'t keep it up overnight!

More than likely it is in the valve body. I am not real familiar with the volvo units, but there should be a three-way control valve, normally solenoid operated. If the valve is leaking, it will bleed pressure off.

 

[msimms]

Re: Volvo outdrive, can\'t keep it up overnight!

Thanks Spannerman, I'll ask that the broker gets it checked out prior to sea trial.

I was wondering if it was worth swapping the whole pump assembly over with the starboard side and seeing if the fault stayed with the leg or moved with pump. No idea if this is feasible or not, a drawing I looked at seems to show the connections amount to a couple of pipes and an electrical connection or two. Almost certainly more involved when faced with it in the flesh!

Cheers

Mark

 

[spannerman]

Re: Volvo outdrive, can\'t keep it up overnight!

Hi Mark, that would confirm it one way or the other, did it on friends Nimbus and confirmed it was the valves in the pump.
Volvo cylinders don't usually have any problems with internal leaks, just external ones around the ram seal and from corrosion where the hoses connect, so just check those, but its pretty obvious as you will lose oil and see it dripping.
Whereas with an internal leak the oil level won't alter.